In the description and claims, the following terms will be used and are defined as follows: an "appendage" is a protrusion from the hull, a "wing" is one kind of an appendage protruding from a hull of a vessel below the waterline and having at least one cambered surface for the purpose of providing lift; "lift" means a force generated by water passing over a cambered surface of a wing which counters the leeward drift force caused by wind on the vessel; an "asymmetric wing" means an appendage having a shape in crossection similar to the crossection of an airplane wing which has upper and lower surfaces of different cambers with span (lengthwise) and chord (crosswise) dimensions; "VMG" (Velocity Made Good) means the velocity of a sailing vessel towards its windward mark; and "drag" means lost energy as water passes over a moving submerged wetted surface which results in the reduction in velocity of a sailing vessel. "Lift/Drag Ratio" is the quantity of lift per unit of drag produced by a moving submerged cambered appendage. What is desired is lots of lift and little drag, the drag being unavoidable.
A "centerboard yacht" is a sailing vessel which has a "trunk" through which a pivoting wing is swingable into and out of the water. In a "sliding keel yacht", the wing is linearly slidable in its "trunk" into and out of the water.
Hydrofoil appendages were also known as "fins" and "wings" during the America's Cup Race of 1982 and at that time were also referred to as "winged keels" and "winglets" by the marine press. They are now referred to as "APPENDAGES" along with rudders, fin keels and keel trim tabs in Rule 19 of the International America's Cup Class Rules.
Ben Lexcen applied a winged keel (for which he filed Australian Patent Application AU-A-85 668/82 in 1982) to the 12 meter AUSTRALIA II yacht which successfully won the America's Cup Race of 1983. The next America's Cup Race in 1987 was won by the USA Yacht which had a winged keel.
The details and operational explanations of Ben Lexcen's winged keel on Australia II appears in the article entitled "KEELS", pages 50-56 of the January 1984 issue of the magazine "YACHT RACING and CRUISING". The author on page 55 using FIGS. 6a and 6b illustrates how Ben Lexcen with his "fins" can produce "keel lift" when the boat is tacking and heeled. As shown in FIG. 6b of the magazine article, when a sailboat is on tack, a force vector is generated perpendicular to and downward away from the slanted lower wing (which corresponds to one of the fins 5 in FIG. 3 of Ben Lexcen's Australian Patent Application) by the water rushing thereover, the horizontal component of the generated force counters and thereby reduces the magnitude of the leeward drift force produced by the wind acting on the sails. FIG. 5 in this application illustrates FIG. 3 in Ben Lexcen's Australian Patent Application when the yacht is sailed with a 20.degree. heel on starboard tack. Its mathematically calculated performance will be used as a "base mark" reference from which to calculate the improved performance of the embodiments shown in the drawings, described in the specification and recited in the claims of this application.
Except for the "AUSTRALIA II" Yacht, other installed appendages by challengers and defenders for the 1983 Americas Cup Race did not improve their performances and were discarded, one reason being that the drag of their wetted surface appendages badly undercut the lift advantages. According to the "NAUTICAL QUARTERLY BOOK" with the title "UPSET: Australia Wins the America's Cup" in the late summer trials of 1982, the American Team could not successfully add "wings" to its defending yacht "MAGIC" (pgs. 81 & 88), nor could the British challenging yacht "VICTORY 83" (pgs. 86 & 88) be successful with "wings" attached to its keel. They failed because their yacht naval architects failed to observe and employ the essential relationships disclosed in the applicant's "Energy Balance" as described hereinafter.
The Deed of Gift for the America's Cup was written in 1853.
In 1887, the Third Gift of Deed was amended to set forth a deed provision for all America Cup Races thereafter as follows:
"Centerboard or sliding keel vessels shall always be allowed to compete in any race for this Cup, and no restrictions nor limitation wherever shall be placed upon the use of such Centerboard or sliding keel, nor shall the Centerboard or sliding keel be considered a part of the vessel for any purpose of measurement." PA1 (a) To reduce the drift energy so that the saved drift energy minus the increased drag energy propels the vessel forwardly, and PA1 (b) To shorten the path of the vessel around the windward mark by decreasing the vessel's leeward drift.
By the New York State Supreme Court (the Trial Court), Appellate Division and Court of Appeals of the State of New York in 1988, the above 1887 Deed Provision was one of the critical factors in upholding the right of the winner of the 1988 America's Cup Race to use a Catamaran. After the 1988 race, the America's Cup Yacht Class was changed from the 12 Meter Class to the new International America's Cup Class (IACC). Of importance is that the above 1887 Deed of Gift Provision "Centerboard or sliding keel vessels shall always be allowed to compete in any race for this Cup . . . for any purpose of measurement." remains unchanged and available to be considered when designing new America's Cup Yachts.